CVE-2026-72809

HIGHPre-NVD 8.08.0—
EchelonGraph scoreMEDIUM confidence

Score 8.0 from GitHub Security Advisory (severity: HIGH) published 2026-08-12. A secondary CVSS source baseline 8.0; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: epss, ghsa, secondary
Elevated
8.0EG
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 0.3%CVSS: 8.0Exploit: Elevated riskExposed services: Not assessed

A fix is available — apply it.

SiYuan versions <= v3.7.2 (patched in v3.7.4) contain an authentication bypass vulnerability in the kernel's CheckAuth function, which grants the administrator role (RoleAdministrator) to any request whose RemoteAddr is loopback (127.0.0.1) for a specific set of endpoints (including /api/system/exit, getNetwork, getWorkspaceInfo, /assets/*, and /export/*). These localhost bypasses sit outside the access auth code gate, so they apply even when an access auth code is configured. Because the fixed-port reverse proxy forwards requests to the kernel over loopback without injecting an authentication token and does not configure trusted proxies, a request forwarded through this proxy reaches the kernel with RemoteAddr = 127.0.0.1. If the fixed-port proxy is bound to a network interface, this could allow a remote unauthenticated attacker to obtain admin access on the affected endpoints; however, per the advisory this remote forwarding behavior was established only by code inspection and was not reproduced end-to-end.

CVSS v3
8.0
EG Score
8.0HIGHmedium confidence
EG Risk
52
EG Risk 52/100CISA SSVC

EG Risk is EchelonGraph's 0–100 priority score: it fuses intrinsic severity with real-world exploitation and automatability so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner. Distinct from the 0–10 EG Score (severity).

How it’s computed
Severity80% × 45%
Exploitation40% × 40%
Automatability0% × 15%
CISA SSVC: Track at low or medium mission impact; Track* at high (mission-essential systems).
Action: A fix is available. Apply it within your standard update timelines.
EPSS PROB
0.3%
EPSS %ILE
20th
KEV
Not listed

CISA SSVCTrack at low or medium mission impact; Track* at high (mission-essential systems).

A fix is available. Apply it within your standard update timelines.

Exploitation public PoC (CISA Vulnrichment) · Automatable no (CISA Vulnrichment) · Technical impact partial (CISA Vulnrichment). Mission impact is CISA's Mission & Well-being decision point, and only you can judge it: high means the affected system is essential to your organisation's mission, or its compromise could cause irreversible harm to people. CISA's decision table

Published

August 12, 2026

Last Modified

August 26, 2026

Advisory Details (2)

Auto-updated Aug 12, 2026
Patch available.
generic

SiYuan before v3.7.4 Authentication Bypass via Localhost Trust | Advisories | VulnCheck

https://www.vulncheck.com/advisories/siyuan-before-authentication-bypass-via-localhost-trust
github Patch Available🟡 PoC Available

Localhost-trust admin bypass on auth-code-gated endpoints, with potential remote reachability via the fixed-port proxy (needs maintainer confirmation) · Advisory · siyuan-note/siyuan · GitHub

https://github.com/siyuan-note/siyuan/security/advisories/GHSA-3mp7-4rh5-jrv9

Vendor Advisories for CVE-2026-72809(1)

These vendors published their own advisory mentioning this CVE — often with vendor-specific remediation steps + affected product lists not in NVD.

Affected Packages

(1 across 1 ecosystem)
Go(1)
PackageVulnerable rangeFix by version rangeDependents
github.com/siyuan-note/siyuan/kernel—
  • every version up to 0.0.0-20260723031701-9c16e9851f0b: fixed in 0.0.0-20260723031701-9c16e9851f0b
—

Weakness Classification(1)

MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.

Data Freshness Timeline

(refreshed 9× in last 7d / 46× in last 30d)

Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. Most recent first.

Showing the most recent 100 of 135 total refreshes for this CVE.

  1. 2026-10-05 14:44 UTCEG score recompute
  2. 2026-10-04 23:22 UTCEPSS rescore
  3. 2026-10-03 19:56 UTCEG score recompute
  4. 2026-10-03 14:26 UTCEPSS rescore
  5. 2026-10-02 21:59 UTCEG score recompute
  6. 2026-10-02 08:19 UTCEG score recompute
  7. 2026-10-01 19:50 UTCEPSS rescore
  8. 2026-09-30 21:54 UTCEG score recompute
  9. 2026-09-29 04:30 UTCEG score recompute
  10. 2026-09-28 14:17 UTCEG score recompute
  11. 2026-09-28 13:52 UTCEPSS rescore
  12. 2026-09-28 01:18 UTCEG score recompute
  13. 2026-09-27 13:48 UTCEPSS rescore
  14. 2026-09-27 09:53 UTCEG score recompute
  15. 2026-09-26 15:59 UTCEPSS rescore
  16. 2026-09-25 03:40 UTCEG score recompute
  17. 2026-09-24 01:42 UTCEG score recompute
  18. 2026-09-23 17:54 UTCEPSS rescore
  19. 2026-09-23 00:05 UTCEG score recompute
  20. 2026-09-21 22:35 UTCEG score recompute
  21. 2026-09-21 21:09 UTCEPSS rescore
  22. 2026-09-21 09:49 UTCEG score recompute
  23. 2026-09-20 20:16 UTCEPSS rescore
  24. 2026-09-19 16:48 UTCEG score recompute
  25. 2026-09-19 03:59 UTCEG score recompute
Show 75 more
  1. 2026-09-18 19:28 UTCEPSS rescore
  2. 2026-09-18 02:29 UTCEG score recompute
  3. 2026-09-17 00:18 UTCEG score recompute
  4. 2026-09-16 14:08 UTCEPSS rescore
  5. 2026-09-16 05:15 UTCEPSS rescore
  6. 2026-09-15 15:22 UTCEG score recompute
  7. 2026-09-15 03:12 UTCEPSS rescore
  8. 2026-09-14 00:35 UTCEG score recompute
  9. 2026-09-12 23:06 UTCEG score recompute
  10. 2026-09-12 15:02 UTCEPSS rescore
  11. 2026-09-12 09:47 UTCEG score recompute
  12. 2026-09-11 21:02 UTCEG score recompute
  13. 2026-09-11 14:53 UTCEPSS rescore
  14. 2026-09-10 19:32 UTCEG score recompute
  15. 2026-09-10 09:35 UTCEPSS rescore
  16. 2026-09-09 05:12 UTCEG score recompute
  17. 2026-09-08 22:01 UTCEPSS rescore
  18. 2026-09-07 19:25 UTCEG score recompute
  19. 2026-09-06 17:34 UTCEG score recompute
  20. 2026-09-06 13:48 UTCEPSS rescore
  21. 2026-09-05 16:04 UTCEG score recompute
  22. 2026-09-04 14:15 UTCEG score recompute
  23. 2026-09-04 05:07 UTCEPSS rescore
  24. 2026-09-03 12:43 UTCGHSA enrichment
  25. 2026-09-02 23:27 UTCEG score recompute
  26. 2026-09-02 23:27 UTCGHSA enrichment
  27. 2026-09-02 14:12 UTCEPSS rescore
  28. 2026-09-02 01:58 UTCEG score recompute
  29. 2026-09-02 01:58 UTCGHSA enrichment
  30. 2026-09-01 13:54 UTCEPSS rescore
  31. 2026-09-01 13:14 UTCEG score recompute
  32. 2026-09-01 13:14 UTCGHSA enrichment
  33. 2026-09-01 04:40 UTCEPSS rescore
  34. 2026-09-01 04:40 UTCEPSS rescore
  35. 2026-09-01 00:29 UTCGHSA enrichment
  36. 2026-08-31 11:43 UTCGHSA enrichment
  37. 2026-08-30 22:52 UTCEG score recompute
  38. 2026-08-30 22:52 UTCGHSA enrichment
  39. 2026-08-30 19:18 UTCEPSS rescore
  40. 2026-08-30 19:17 UTCEPSS rescore
  41. 2026-08-30 10:07 UTCEG score recompute
  42. 2026-08-30 10:06 UTCGHSA enrichment
  43. 2026-08-30 01:22 UTCEPSS rescore
  44. 2026-08-29 21:18 UTCGHSA enrichment
  45. 2026-08-29 08:33 UTCEG score recompute
  46. 2026-08-29 08:32 UTCGHSA enrichment
  47. 2026-08-28 21:42 UTCEPSS rescore
  48. 2026-08-28 10:12 UTCGHSA enrichment
  49. 2026-08-27 20:39 UTCEG score recompute
  50. 2026-08-27 20:39 UTCGHSA enrichment
  51. 2026-08-27 14:25 UTCEPSS rescore
  52. 2026-08-27 07:21 UTCGHSA enrichment
  53. 2026-08-26 17:16 UTCGHSA enrichment
  54. 2026-08-26 16:28 UTCEG score recompute
  55. 2026-08-26 16:28 UTCGHSA enrichment
  56. 2026-08-26 14:47 UTCEPSS rescore
  57. 2026-08-26 03:36 UTCGHSA enrichment
  58. 2026-08-25 14:51 UTCGHSA enrichment
  59. 2026-08-25 02:06 UTCEG score recompute
  60. 2026-08-25 02:06 UTCGHSA enrichment
  61. 2026-08-24 13:22 UTCEG score recompute
  62. 2026-08-24 13:22 UTCGHSA enrichment
  63. 2026-08-24 00:37 UTCGHSA enrichment
  64. 2026-08-23 11:52 UTCGHSA enrichment
  65. 2026-08-22 23:08 UTCGHSA enrichment
  66. 2026-08-22 10:23 UTCEG score recompute
  67. 2026-08-22 10:23 UTCGHSA enrichment
  68. 2026-08-21 23:49 UTCEPSS rescore
  69. 2026-08-21 21:38 UTCGHSA enrichment
  70. 2026-08-21 08:53 UTCGHSA enrichment
  71. 2026-08-20 20:06 UTCGHSA enrichment
  72. 2026-08-20 07:21 UTCGHSA enrichment
  73. 2026-08-19 18:36 UTCEG score recompute
  74. 2026-08-19 18:36 UTCGHSA enrichment
  75. 2026-08-19 17:04 UTCEPSS rescore

Related CVEs(same product + same CWE)

Frequently asked(5)

What is CVE-2026-72809?
CVE-2026-72809 is a high vulnerability published on August 12, 2026. SiYuan versions <= v3.7.2 (patched in v3.7.4) contain an authentication bypass vulnerability in the kernel's CheckAuth function, which grants the administrator role (RoleAdministrator) to any request whose RemoteAddr is loopback (127.0.0.1) for a specific set of endpoints (including…
When was CVE-2026-72809 disclosed?
CVE-2026-72809 was first published on August 12, 2026, with the most recent update on August 26, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-72809 actively exploited?
CVE-2026-72809 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0.3% probability of exploitation in the next 30 days (20th percentile of EPSS-scored CVEs).
What is the CVSS score of CVE-2026-72809?
CVE-2026-72809 has a CVSS base score of 8.0 (a secondary CVSS source that NVD displays; NVD's own analysis pending).
How do I remediate CVE-2026-72809?
A fix for CVE-2026-72809 is available: update to the fixed version the vendor names in its advisory. The vendor advisories EchelonGraph has for CVE-2026-72809 are linked in the Vendor Advisories panel on this page.

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